Waterproof abrasive fabric and method of making the same



. gums and resins in thebinder, the flexibility of fabric base is first impregnated with a water- UNITED STATES PATENT OFFICE Les-1,407 wn'smoor ABRASIVE ranmc AND rm'rnon or MAKING 'rna sans Frank Joseph 011ml, Brooklyn, N. Y., assignor to Behr- Corporation, Brook yn, N. Y., a corporation of New York No Drawing. Application September 15, 1927, Serial No. 219,816. Renewed June 11, 1934 15 Claims. ((71. 51-280) This invention relates to a method of making I have now discovered a new method of making an extremely flexible, waterproof,- and durable abrasive fabrics which will overcome the disadarticle in the nature of sandpaper or cloth. vantages noted hereinabove. The new abrasive At the present time,alargeportion of the waterfabrics will sand the surface under treatment 5 proof sandpaper on the market is used in the auwithout scratching, will provide a bond between 5 tomobile industry for body finishing. In the use the abrasive particles and the binder, and have of sand paper for this purpose the surface to be practically no tendency to crack, will hold the treated is'flrst well wetted with water and is then abrasive particles tenaciously even under wet and sanded with an abrasive fabric which has previcrumpled operating conditions, and will preserve ouslybeen immersed in water. There are many an extremely flexible character in such'uses. 10 crevices and other irregular surfaces on an auto- My invention distinguishes over abrasive fabrics mobile body, and, in order to sand and abrade including the gum varnish products in that they such parts properly and effectively it is highly dewill not only have a greater initial flexibility but sirable that the abrasive fabric should be exwill also retain the flexibility over a considerable tremely flexible and should be capable of being and materially longer period of time. 15

' crumpled without cracking the abrasive bond. In the ordinary course of trade it is possible to Ordinary waterproof sandpaper when so keep my novel abrasive fabric in regular industrial crumpled frequently caused the abrasive bond to storage for the usual commercial periods of storcrack due to lack of sufficient flexibility of the ing with only negligible effects on the fabric so fabric, and the sharp edges of such cracks in the that the product, after being taken from the storcrumpled sandpaper cause the formation of relaage, still retains substantially all of its original tively deep objectionable scratches on the finflexibility. Moreover, when the stored fabric is ished surface of the automobile body. used it is wetted with water and its flexibility is It is one of the objects of the present invenfurther increased so that it can then be crumpled tion to prevent the formation of such cracks and in use without cracking the abrasive bond. 25

to provide a waterproof abrasive fabric which can Generally speaking, my invention consists in be crumpled in'the wet condition while preserving, covering a surface of a fabric base with a coatthroughout, the requisite flexibility. ing or film of polymerized drying oil inwhich is Heretofore the waterproof abrasive fabric embedded an abrasive material or a layer of 39 which was generally used had a binder for the abrasive particles. A film of such oilissuperiman abrasive particles consisting of, or at least conposed upon a surface of a fabric and constitutes taining, a gum varnish. When gum varnish was a matrix which adhesively unites or secures a used as the binder, the abrasive fabric or sandplurality of abrasive particles to the fabric and paper was fairly flexible while new. After the which completely incorporates and anchors the passage of arelatively short period of time, howparticles in such a manner that they are held 35 ever, the fabric began to lose its flexibility due tenaciously to the fabric even under severe rubto the oxidation and aging of the varnish binder. bing action. I When the aforesaid fabrics were used they were Attention at this point is directed to the fact therefore relatively brittle and likely to crack that the oil used in making my new sandpaper is fairly easily. Whenever the cracked abrasive a polymerized oil as distinguished from nonbond began to scratch and mar the surface under polymerized oils, i. e. the oil is prepolymerized treatment, indicating that the abrasive fabric before it is used. This is a distinction of mate-. was no longer satisfactory or fit for use, a new rial importance as the action and behavior of the piece of abrasive fabric had to be substituted. In 'two types of oil, the polymerized oil on the one the effort to prolong the life of such sandpaper, hand and the non-polymerized oil on the other, it was proposed to use gums or resins such as are quite different physically and chemically, kauri, copal, and dammar to increase the adespecially in their relation to the various elehesion and hardness of the binder. Due, howments which make up the finished product. ever, to the presence of these relatively brittle In the preferred form of my invention the the abrasive fabric was detrimentally reduced. p ofin agent u h as p y d ng 011 or Consequently the abrasive. fabrics containing the like. After the impregnated base is properly gum-oil varnishes were subject to manydisaddried, a coating or film of polymerized drying vantages and were not especially suited for such oil is applied to one of the surfaces of such base.

uses as the finishing of automobile bodies. Immediately after the application of the oil abrasive particles are sprinkled upon the coated fabric so that a layer. of abrasive particles or grains is embedded and incorporated in the film of oil. The abrasive coated fabric is dried and then is preferably covered-with a second coat or'film of polymerized drying oil so as to completely envelope practically the entire abrasive surface. When this covered surface is dried, the abrasive fabric is ready for use or for sale. In order to obtain the best results in carrying out the aforesaid process, it is preferable to use an oil like linseed or China-wood which is highly refined and purified before polymerization. Such an oil is substantially devoid of free fatty acids and the glycerides of saturated acids.

There are several methods which may be employed for polymerization of the drying oil. The more important of these methods are the usual kettle heating, heating in the absence of oxygen or in an atmosphere of carbonic acid gas, and.

heating in'vacuum. Although any one of these methods may be used, I have found that the best results are obtained by using an oil made by the vacuum method. In the use of the other methods of polymerization the temperature is usually 200 to 300 degrees higher than that employed in the vacummethod. The high heat used in these other methods causes a certain amount of breaking down of molecules with the resultant formation of acids and volatile matter and the production of an impure product. In the vacuum method very little of these acids are formed because of the lower heat employed and because of the removal of the volatile cleavage products by vacuum. With this method there is very little oxidation. The vacuum method, therefore, produces' what may theoretically be considered the purest form of polymerization, and the final viscous product is the purest form of drying oil. The polymerization is carried on until the oil has reached its saturation point, i. e., the point just before the oil will begin to gel on further heating. A linseed oil so treated will, generally speaking, have a final iodine number of approximately 122, an acid number of 2 to 3, a saponification value of about 189, and a specific gravityin the neighborhood of 0.974. In usingthis oil its viscosity is thinned down with a solvent such as petroleum spirits or vamolene until reduced to the desired consistency for coating and for sizing thevarious fine and coarse grades of abrasive fabrics or sand paper. To hasten the drying of this oil, I have found that the linoleates of cobalt and lead are best suited for this purpose. I may also use the resinate of these metals or a mixture of a paste of linoleates and resinates. The

' drier that I particularly use is a mixture of a paste of cobalt linoleates containing 5.6% cobalt metal and a paste of lead linoleates containing 18% lead metal. The proportions are nine parts by weight of the former to six parts by weight of the latter. The amount of this mixture added to the oil is varied from 5% to by weight depending on the particular grade of sandpaper that is to be niade. The coarse grades require a thicker film of oil, and, therefore, need more of the drying agent.

An illustrative example of carrying my invention into practice will be described hereinafter, although it is to be understood that the scope of the invention is not to be limited by the materials .and amounts given in this example,

I take a given quantity of the very viscous polymerized oil made by the vacuum method and thin it with vamolene or petroleum spirits to the desired viscosity. An appropriate amount of the paste driers, above mentioned, is weighed out and thinned with vamolene to the desired consistency. After proper thinning the driers are mixed and thoroughly incorporated in the thinned polymerized oil. The paper or fabric to be coated with abrasive is well impregnated with thisthinned solution of polymerized oil containing driers and is then dried on racks preferably by means of heated air. After the impregnated fabric is dried it is re-rolled and passed through the coating machine again, printed on one side and coated on the opposite surface with the solution. Immediately thereafter it is sprinkled or covered with a coating or layer of abrasive particles which are preferably of a predetermined size. The abrasive employed may be selected to meet the required conditions and may be an artificial abrasive such as silicon carbide, aluminum oxide, or the like, or a natural abrasive such as garnet, flint, or the like. The abrasive paper is again carried along on racks into a heated chamber maintained at about 150 F. by heated air. After the oil film has acquired its set, which usually takes approximately several hours, the paper is again passed through the machine for the application of a final sizing coat of polymerized oil to .envelope the sand surface. when this sizing coating is dried by air, heated to about 150 F., the abrasive fabric or sandpaper is taken from the drying racks and is then cut into small sheets or small rolls which are ready for use or for sale in the markets.

In some instances where the coating surface of the primary fabric or paper is very porous, such as very absorbent paper or cloth products, I add to the binder of oil and drier hereinbefore described, an inert filler material such as clay, fullers earth, or other appropriate material.

,The filler imparts body to the binder and prevents the latter from being easily absorbed.

It is to be noted that my'invention provides an abrasive fabric containing a binder substance which consists practically wholly of a polymerized oil that has but little oxidation and further polymerization to undergo before setting to a tough, extremely flexible, and durable film. Due to the polymerization of the oil, the film does not age in storage and the abrasive fabric retains its fiexibility and toughness.

I claim:

1. A waterproof abrasive fabric having a fiexible character comprising a waterproof fabric base, and a film in the nature of a matrix containing abrasive particles and consisting of polymerized oil, lead linoleate and cobalt linoleate,

united to said fabric base to form an integral product.

2. A waterproof abrasive fabric having a fiexible character comprising a fabric base, and a film in the nature of a matrix containing a layer of abrasive particles and consisting of polymerized oil, lead linoleate, cobalt linoleate, leadv resinate, and cobalt resinate adhesively secured to a surface of said fabric base.

3. A waterproof abrasive fabric having a fiexible character comprising a waterproof impregnated fabric-base, and'a film in the nature 'of a containing a layer of abrasive particles and consisting of polymerized oil, driers, and inertfiller material incorporated on a surface of said fabric base.

4. A waterproof abrasive fabric having a fiexible character comprising a waterproof impregnatedfabricbase,andafilminthenatureofa ing a mixture of linoleates and resinates of lead.

and'cobalt, said material being constituted to retain flexibility for a period of industrial storage.

5. An abrasive fabric comprising a base conistituted of a fabric, a film coating containing an oil covering a surface of said fabric and a plurality of abrasive particles embodied in said film coating of such oil, said oil coating being characterized by having a minimum oxygen absorption factor during setting, resulting from pre-polymerization whereby flexibility of the fabric and coating will be retained throughout prolonged periods of storage of said'abrasive fabric.

6. An abrasive fabric comprising a fabric base protected by a waterproof agent,'a film coating superimposed upon a surface of said base containing an oil and abrasive particles anchored in said film coating, said film coating being characterized by including an oil having aminimum oxygen absorption factor during setting, resulting from prepolymerization whereby flexibility of the fabric and film coating will be retained throughout ,prolonged periods of storage of said abrasive fabric. g

7. An abrasive fabric comprising a fabric base impregnated with an oil and a superimposed film coating of 'such oil, the superimposed coating including abrasive particles, said impregnated oil and film coating being characterized by having a minimum oxygen absorption factor during setting resulting from pre-polymerization, whereby said abrasive fabric will be extremely flexible and will retain said flexibility throughout prolonged secured thereto and a film coating containing an oil for the last layer superimposed over said abrasive particles, all of said film coatings being characterized by the oil thereof having a minimum oxygen absorption factor during setting, resulting from pre-polymerization whereby flexibility of the fabric and film coatings will be retained throughout prolonged periods of storage. '9. An abrasive fabric comprising a fabric base, a film coating of an oil including a drying agent covering the surface of said fabric, a layer of abrasive particles embedded in said film coating and a coating similar to said first coating sup'erimposed over said abrasive particles, the oil of said film coating on said fabric and abrasive particles being characterized/by having a minimum oxygenabsorption factor during setting, resulting from prepolymerization whereby a flexible abrasive fabric is obtained, retaining the fiexibility throughout prolonged periods of storage.-

' 10. An'abrasive fabric comprising a fabric base impregnated with an oil, a film coating consisting of an oil and a ing agent covering said-impregnated fabric, brasive particles anchored in .said last film coating and presenting an abrasive surface and an enveloping film coating for said abrasive surface consisting of an oil and a dry- 75 a 11. A waterproofabrasive fabric comprising a waterproof impregnated fabric base, a layer of abrasive grains adhesively united to said base and a film coating consisting of. an oil and a drying I sive fabric having a flexible character, which comprises preparing a viscous oil polymerized to a condition where the absorption of oxygen during subsequent setting of said oil is minimized and having a consistency amenable to retaining a layer of abrasive particles. thinning said oil to a consistency for spreading, applying the thinned polymerized oil in the form of 'a film to a dried fabric base impregnated with a waterproofing agent and incorporating a layer of abrasive particles in said film. v

13; The process of making a waterproof abrasive fabric having a flexible character which comprises preparing a viscous oil by polymerization, the polymerization being carried toa condition where the absorption of oxygen during subsequent setting of said oil is minimized and having a con sistency for retaining a layer of abrasive particles when in film form, thinning said oil to a consistency appropriate for spreading to a fabric base, applying a film of the aforementioned thinned, polymerized oil to a fabric base which has been previously impregnated with a wateri proofing agent and dried, incorporating a layer of abrasive particles in said film, drying the fabric thus prepared to a condition leaving the oil film flexible and then applying over the composite film including the abrasives an additional coat of such polymerized oil-first prepared and drying said coat, leaving the last coating of substantially the same flexibility as the first film.

14. The process of making waterproof abrasive fabrics having a flexible character which comprises preparing a viscous oil by polymerization to a condition where absorption during sub sequent setting of the oil is minimized and having a body appropriate for retaining a layer of abrasive particles, thinning said 611 to a consistency appropriate for application to a fabric by spreading, adding a. drying agent to the polymerized oil so thinned and spreading a film of this mixture to an impregnated and waterproofed fabric base and'incorporating a layer of abrasive parfabrics having a flexible character which comprises preparing a viscous oil by polymerizing to a condition whereby absorption of the oxygen during the subsequent setting of said 011 is minim-. ized, the polymerization being carried to. an extent where it has body sufficient to carry a layer of abrasive particles, thinning said ofl to a 9011- sistency appropriate for spreading to a fabric base, adding a dryin'g agent to said polymerized oil so thinned, impregnating a fabric base with the aforesaid thinned polymerlzedoil, subjecting the fabric base so treated to the action of hot air 'to dry said fabric, leaving the'fabric and oil mounted thereon flexible, applying a second boating of the aforesaid thin oil and coating a layer of abrasive particles thereover, and then dryingthe fabric including'the coating of abrasive particles to a condition leaving the entire composite flexible.

co I 

